Please help me fix oscillating pitch control

The plane I am currently building, a B767, has an oscillating pitch control, where pitching any way will make the nose of the plane go up and down, and this also causes the altitude hold to not work. i have hidden small rudders in the front fuselage to help with pitch control, as i normally do with planes, however this neither made the issue worse or better. just more responsive. i am at a loss currently, please help, (modified workbench needed to spawn it)https://steamcommunity.com/sharedfiles/filedetails/?id=3667094357